1. Field of the Invention
This invention relates generally to a seat back for use in vehicles and, more specifically, to a seat back cushion used by the driver or a passenger in private and/or commercial vehicles which produces a massaging effect.
2. Description of the Prior Art
Drivers and passengers in motor vehicles often suffer from bodily complaints during long runs. These complaints may be very distressing and may in the long term lead to permanent impairment of health, more particularly, among truck and bus drivers who are subject to such stress for long periods of time. It also is to be noted that such impairment of bodily wellbeing may have effects on the state of mind; that is, the driver's attention may be distracted in traffic and there is generally a disadvantageous effect on the mental health of the driver or passenger which is hardly conducive to concentration on other traffic.
Many attempts have been made to design seats which are more ergonomic in structure. The results so far have only led to gradual changes in design with a slight improvement in comfort since all such improved seat designs have been static. In a vehicle, however, it is necessary for the driver or passenger to stretch himself or herself, that is to say he or she has to perform a dynamic act having a massaging effect.
Even where seat structures have been provided with massaging apparatus, the results have not proven entirely satisfactory. For example, in U.S. Pat. No. 3,483,862 issued Dec. 16, 1969 in the name of Shigeo Takeuchi, there is disclosed a therapeutic spot pressure apparatus which utilizes a fluid pressure generating mechanism to expand portions of an armchair to cyclically apply spot pressure to points on the human body sitting thereon. However, the structure is rather intricate in requiring separate pressure conduit lines to each of the expansible bellows-like members which apply the spot pressure. Also, the expansible units are not coupled together by pressure valves which are deemed necessary to provide an effective wave-like massaging motion.
In U.S. Pat. No. 3,678,520 issued July 25, 1972 in the name of Ronald James Peter Evans, there is disclosed a pressure pad for bed patients which includes collapsible air cells that are inflated and deflated from time to time. Here, again, the air cells are not coupled together by pressure valves for effective wave motion.
In U.S. Pat. No. 3,982,786 issued Sept. 28, 1976 in the names of Gerard Burgin et al., there is disclosed a seat and back rest cushion composed of expansible portions, some of which are interconnected by valves to vary the pressure therein upon a change in seating position. While the seat provides comfort by accommodating body movements, there is no wave massaging effect.
In U.S. Pat. No. 4,583,255 issued Apr. 22, 1986 in the names of Tadashisa Mogaki et al., there is disclosed a mat having separate expansible air chambers subjected to pressure changes to induce a wave motion for purpose of massage. Here, again, the chambers are not coupled together by pressure valves. Instead, a separate supply line is provided for each chamber which renders the mat cumbersome to manufacture. Also, the mat is not readily adaptable for use as a seat back in a vehicle.
In French Patent No. 2,373,996 dated Aug. 18, 1978 in the name of Roger Tallon, there is disclosed a chair composed of flexible tubular compartments subjected to fluid flow under pressure. However, the compartments are not interconnected with one another by valves so that there is no wave produced for purpose of massage.
The present invention improves over these known devices in the manner hereinafter described.